Hillary Rodham Clinton in New Hampshire on Monday. Sidney Blumenthal, a close confidant of Mrs. Clinton, turned over emails about Libya to a House committee.CreditIan Thomas Jansen-Lonnquist for The New York Times

WASHINGTON — Emails that a longtime confidant to Hillary Rodham Clinton recently handed over to the House committee investigating the 2012 attacks in Benghazi, Libya, raise new questions about whether the State Department and Mrs. Clinton have complied with a series of requests from the panel.

The emails, provided by Sidney Blumenthal, a close adviser to Mrs. Clinton, include information about weapons that were circulating in Libya and about the security situation in Benghazi in the year and a half before the attacks. The committee has asked the State Department and Mrs. Clinton several times in the past year for emails from her and other department officials about “weapons located or found in” Libya and about the decision to open and maintain a diplomatic mission in Benghazi.

The emails from Mr. Blumenthal have widened a rift between the State Department and the committee. State Department officials said that they had complied only with requests and subpoenas related directly to the attacks because the committee’s demands were too broad. The department has “provided the committee with a subset of documents that matched its request and will continue to work with them going forward,” said a spokesman, Alec Gerlach.

But the panel has called that an excuse to protect Mrs. Clinton and to slow the investigation of the attacks, which occurred on Sept. 11, 2012, and resulted in the deaths of four Americans, including Ambassador J. Christopher Stevens.

It is not clear whether the State Department possesses the emails between Mrs. Clinton and Mr. Blumenthal and did not hand them over. It is also possible that Mrs. Clinton never provided them to the department and deleted them off the server that housed the personal account she used exclusively when she was secretary of state.

Mr. Gerlach said that the committee had not told the department which emails Mr. Blumenthal handed over and that it would take some time for officials to determine whether the department had the emails.

In response to a subpoena from the committee, Mr. Blumenthal on Friday handed over dozens of pages of emails between him and Mrs. Clinton. The emails are similar to others between Mr. Blumenthal and Mrs. Clinton that were provided to the committee by the State Department in February.

Those included dozens of memos about Libya that Mr. Blumenthal sent to Mrs. Clinton. She forwarded many of them to her deputies to seek feedback. The deputies often said that Mr. Blumenthal’s information was false or misleading.

Mr. Blumenthal, a former aide to President Bill Clinton, is scheduled to be deposed by the committee on Tuesday. Its chairman, Trey Gowdy, Republican of South Carolina, wants to question him about where he was getting his information and why he was writing intelligence memos for Mrs. Clinton. At the time, Mr. Blumenthal was being paid by the Clinton Foundation.

In the emails he gave to the committee, there are several references to weapons in Libya. One describes how a Libyan opposition leader feared that the United States did not want to provide weapons to opposition groups because the arms could fall into the hands of Al Qaeda or other radical Islamist groups. Another email included a list of weapons said to be possessed by the government of Col. Muammar el-Qaddafi.

Last year, the State Department asked Mrs. Clinton for any documents she had that may be government records. In response, she gave the department about 30,000 emails that she said related to her work. The State Department in February provided the committee with about 900 pages of Mrs. Clinton’s emails that the department said were handed over in response to the panel’s requests, which included a subpoena that the committee had sent to Mrs. Clinton. Mrs. Clinton has said that she deleted about 30,000 other emails from the account that were personal. Republicans have contended that this gave Mrs. Clinton an opportunity to cherry-pick the documents that would be considered government records.

After The New York Times first reported in March that she had exclusively used the personal email account, she said that she had asked the State Department to make her emails public. That process is likely to take months, if not years.

“The department is working diligently to publish to its public website all of the emails received from former Secretary Clinton through the FOIA process,” Mr. Gerlach said, referring to the Freedom of Information Act.